Charged particle beam lithography apparatus and charged particle beam pattern writing method

ABSTRACT

A charged particle beam lithography apparatus, includes a plurality of multiple-beam sets, each of which including a plurality of irradiation sources each generating an independent charged particle beam, a plurality of objective deflectors, each arranged for a corresponding charged particle beam, and configured to deflect the corresponding charged particle beam to a desired position on a substrate, and a plurality of electrostatic or electromagnetic lens fields each to focus the corresponding charged particle beam on the target object; a plurality of common deflection amplifiers, arranged for each multiple-beam set, and each of the plurality of common deflection amplifiers being configured to commonly control the plurality of objective deflectors arranged in a same multiple-beam set; a plurality of individual ON/OFF mechanisms configured to individually turn ON/OFF a beam irradiated from each irradiation source; and one or more multiple-beam clusters including the plurality of multiple-beam sets.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Divisional of U.S. application Ser. No. 16/228,824filed Dec. 21, 2018, which is based upon and claims the benefit ofpriority from prior Japanese Patent Application No. 2017-249436 filed onDec. 26, 2017 in Japan, the entire contents of each of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

Embodiments described herein relate generally to a charged particle beamlithography apparatus and a charged particle beam pattern writing methodand relates to, for example, a method of writing a pattern directly on awafer using multiple beams.

Related Art

A lithography technique which leads development of micropatterning of asemiconductor device is a very important process for exclusivelygenerating a pattern in semiconductor manufacturing processes. In recentyears, with an increase in integration density of an LSI, a circuit linewidth required for semiconductor devices is getting smaller year byyear. Here, the electron beam pattern writing technique has inherentlyexcellent resolution, and a pattern is directly written onto asemiconductor wafer using an electron beam without going through a maskfor exposure.

Further, if the exposure area of a target object is S, the resistsensitivity is d, and the beam average current is Ib, the patternwriting time Ttot is given by Ttot=Sd/Ib+Tne if a useless time Tne suchas the movement time of a beam is excluded. That is, in order to shortenthe exposure time, it is clear that the beam average current Ib needs tobe increased and/or the useless time Tne needs to be shortened.

In the variable shaped beam system mainly used in the conventionalelectron beam writing, the current density is not dependent on the beamsize in general, so that the beam size becomes small as the patternbecomes finer and thus, the beam average current Ib becomes smaller. Inaddition, the time Tne required for moving a beam increases. Therefore,it is difficult to shorten Ttot.

As a system of shortening the time Tne and increasing the average beamcurrent Ib, for example, a lithography apparatus using multiple beams isknown. Compared with the case in which one electron beam is used towrite a pattern, more beams can be irradiated at a time by usingmultiple beams and so the beam average current Ib can be increasedregardless of the pattern, and also many beams are deflected at a timeand so an increase of the time Tne can be suppressed and therefore,throughput can be improved significantly. In such a lithographyapparatus of multiple-beam mode, for example, an electron beam emittedfrom an electron gun assembly is passed through a mask having aplurality of holes to form multiple beams, each beam is subjected toblanking control, each beam that is not shielded is reduced by anoptical system, and multiple beams as a whole are collectively deflectedby a common deflector before being shot at a desired position on atarget object.

In such a multiple-beam pattern writing apparatus, one beam emitted fromone irradiation source is divided into multiple beams and thus, there isa limit to increasing the amount of beam current in multiple beams as awhole. Therefore, further improvements in throughput are limited.

Also, a lithography apparatus using a multi-column that combineselectron beam columns, each including an electron gun assembly, a lens,and a deflector and serving one electron beam has been studied. In sucha multi-column lithography apparatus, each column takes charge of one ofa plurality of dies (chips) of the same pattern formed on asemiconductor wafer for pattern writing. In the multi-column lithographyapparatus, each beam is emitted by an individual electron gun assemblyand thus, it may be possible to increase the amount of current. However,in the multi-column lithography apparatus, individual columns arecontrolled independently and thus, the number of deflection amplifiersof the deflector also increases accordingly. When one deflector isconstructed of, for example, eight electrodes, eight deflectionamplifiers are required for each beam. Thus, when, for example, 2000beams are irradiated at a time as multiple beams, 16,000 deflectionamplifiers are required and the control of 16000 deflection amplifiersis required. Therefore, practically, there is a limit to the number ofbeams that can be mounted, and it becomes difficult to fully demonstratethe unique performance of multiple-beam pattern writing such asimprovement of pattern writing throughput. Even if additional columnscan be added, the number of beams is limited because the number equal tothe number of dies (chips) formed on one wafer becomes the upper limitand so the number of beams is limited and there is a limit to the massproduction of semiconductor wafers.

In contrast, a lithography apparatus in which beams are emitted fromeach of a plurality of electron gun assemblies to form multiple beams asmany as the number of electron gun assemblies and the multiple beams asa whole are collectively focused and deflected by a common electronoptics to irradiate a desired position on a target object with themultiple beams is also proposed (see Published Unexamined JapanesePatent Application No. 07-192682 (JP-A-07-192682), for example). In sucha configuration, each beam is emitted by an individual electron gunassembly so that the amount of current can be increased. However, thediameter size of the whole beam becomes large and so the electrode usedfor the deflector becomes large. Therefore, the number of beams that canbe mounted is limited and the mass production of semiconductor wafers isstill limited.

BRIEF SUMMARY OF THE INVENTION

According to one aspect of the present invention, a charged particlebeam lithography apparatus, includes:

-   -   a plurality of multiple-beam sets, each of which including        -   a plurality of irradiation sources each generating an            independent charged particle beam,        -   a plurality of objective deflectors, each arranged for a            corresponding charged particle beam, and configured to            deflect the corresponding charged particle beam to a desired            position on a substrate as a target object, and        -   a plurality of electrostatic or electromagnetic lens fields            each to focus the corresponding charged particle beam on the            target object;    -   a plurality of common deflection amplifiers, arranged for each        of the plurality of multiple-beam sets, and each of the        plurality of common deflection amplifiers being configured to        commonly control the plurality of objective deflectors arranged        in a same multiple-beam set;    -   a plurality of individual ON/OFF mechanisms configured to        individually turn ON/OFF a beam irradiated from each of the        plurality of irradiation sources; and    -   one or more multiple-beam clusters including the plurality of        multiple-beam sets.

According to another aspect of the present invention, a charged particlebeam pattern writing method includes:

-   -   continuously moving a plurality of substrates aligned in a        predetermined direction in the predetermined direction; and    -   writing a pattern on the plurality of substrates by using a        plurality of multiple-beam sets, each irradiating multiple        beams, so that each multiple-beam set of the plurality of        multiple-beam sets sequentially writes a portion of the pattern        on a different one or more of exposure pixel groups in a same        small region, on a same substrate, smaller than each die region        of a plurality of die regions to form a same pattern, the        plurality of die regions provided on each substrate of the        plurality of substrates, in a state where the plurality of        substrates is continuously moved in the predetermined direction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram showing the configuration of alithography apparatus according to a first embodiment;

FIGS. 2A to 2C are diagrams showing an example of a system configurationof a multiple-beam cluster according to the first embodiment;

FIG. 3 is a diagram showing another example of the system configurationof a multiple-beam block according to the first embodiment;

FIG. 4 is a diagram showing another example of the system configurationof the multiple-beam cluster according to the first embodiment;

FIG. 5 is a diagram showing another example of the system configurationof a multiple-beam set according to the first embodiment;

FIG. 6 is a diagram showing still another example of the systemconfiguration of the multiple-beam set according to the firstembodiment;

FIG. 7 is a diagram showing still another example of the systemconfiguration of the multiple-beam set according to the firstembodiment;

FIG. 8 is a diagram showing an example of an internal configuration ofan electron beam column according to the first embodiment;

FIG. 9 is a sectional view showing an example of an electrostatic lensaccording to the first embodiment;

FIG. 10 is a sectional view showing another example of the electrostaticlens according to the first embodiment;

FIG. 11 is a top view showing an example of the relationship betweenobjective deflectors and deflection amplifiers according to the firstembodiment;

FIG. 12 is a diagram showing an example of a plurality of chip regionsformed on a semiconductor substrate according to the first embodiment;

FIG. 13 is a diagram illustrating an example of a pattern writingprocedure according to the first embodiment;

FIG. 14 is a diagram illustrating an example of the pattern writingprocedure according to the first embodiment;

FIG. 15 is a diagram showing an example of a pattern writing techniquewhen a pattern is written in a small region in the chip region in thefirst embodiment with the multiple-beam set;

FIG. 16 is a diagram illustrating an example of a method of performingcontinuous pattern writing on a plurality of substrates according to thefirst embodiment;

FIG. 17 is a diagram illustrating another example of the method ofperforming continuous pattern writing on the plurality of substratesaccording to the first embodiment;

FIG. 18 is a diagram illustrating still another example of the method ofperforming continuous pattern writing on the plurality of substratesaccording to the first embodiment;

FIG. 19 is a diagram showing another example of the internalconfiguration of the electron beam column according to the firstembodiment;

FIG. 20 is a diagram showing still another example of the internalconfiguration of the electron beam column according to the firstembodiment;

FIG. 21 is a diagram showing still another example of the internalconfiguration of the electron beam column according to the firstembodiment;

FIG. 22 is a diagram showing still another example of the internalconfiguration of the electron beam column according to the firstembodiment;

FIG. 23 is a top view showing an example of an electrostatic lens arrayaccording to the first embodiment;

FIG. 24 is a sectional view showing an example of the electrostatic lensarray according to the first embodiment; and

FIG. 25 is a diagram showing an example of the shape of a cluster of thefirst embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, in an embodiment, a lithography apparatus and a methodcapable of improving the throughput of multiple-beam pattern writing andmass-producing semiconductor substrates will be described.

In Embodiment described below, the configuration using an electron beamwill be described as an example of a charged particle beam. However, thecharged particle beam is not limited to an electron beam, and a beamsuch as an ion beam using charged particles may also be used.

First Embodiment

FIG. 1 is a conceptual diagram showing the configuration of alithography apparatus according to a first embodiment. In FIG. 1, alithography apparatus 100 includes a pattern writing mechanism 150 and acontrol system circuit 160. The lithography apparatus 100 is an exampleof the charged particle beam lithography apparatus. The pattern writingmechanism 150 includes a pattern writing chamber 102. In the patternwriting chamber 102, a plurality of multiple-beam clusters 16 and astage 105 are arranged. In the example of FIG. 1, the case where theplurality of multiple-beam clusters 16 is arranged is shown, but thepresent embodiment is not limited to this and one or more multiple-beamclusters 16 may be arranged. In an upper portion of the stage 105, forexample, a plurality of electrostatic chucks for fixing a substrate 101is provided. By the operation of a transport system (not shown), thesubstrate 101 is transported onto the stage 105 or taken out from thestage 105 to the outside. By such an operation, a plurality ofsubstrates 101 on which a pattern is to be written is arranged on thestage 105 with the surface on which a pattern is to be written directedupward. The position of the stage 105 is measured by a positionmeasuring mechanism 138 such as a laser interferometer or a linear scaleto measure the position of each of the substrates 101. The position ofeach of the substrates 101 can be obtained relative to the stageposition to be measured. It is desirable to provide a plurality of suchposition measuring means. A plurality of measuring means in the ydirection is provided when the stage moving direction for patternwriting is the x direction. The wafer position in the y direction ineach multiple-beam set 12 is estimated from the outputs of a pluralityof y direction measuring means and the value and the estimated value ofthe wafer position in the x direction are used for stage tracking. Eachof the multiple-beam clusters 16 is constructed of one or moremultiple-beam blocks 14. Each of the multiple-beam blocks 14 isconstructed of a plurality of multiple-beam sets 12. In other words, themultiple-beam cluster 16 is constructed of a plurality of multiple-beamsets 12. The multiple-beam set 12 is a kind of multiple-beam column. Anelectron beam column 10 is defined as a unit having an electron source,a lens mechanism for converging and focusing an electron beam emittedfrom the electron source on the surface of the substrate 101, and anobjective deflector. The lens mechanism in the electron beam column 10unit includes a case where the lens mechanism is a portion of a lensarray in which a plurality of lenses is arranged. The lens mechanismforms an electrostatic or electromagnetic lens field for focusing anelectron beam on the target object surface. Each of the multiple-beamsets 12 has a plurality of electron beam columns 10 and is defined asbeing configured such that a common deflector drive input signal isinput into each objective deflector in the same multiple-beam set 12 andeach objective deflector is driven by a common deflector drive electricfield or current. Further, in the multiple-beam set 12, each of theelectron beam columns 10 belonging to the multiple-beam set 12 isattached to a common mechanical fixing means. In other words, each ofthe plurality of multiple-beam sets 12 includes a plurality ofirradiation sources each generating an independent electron beam and aplurality of objective deflectors each arranged for a correspondingelectron beam to deflect the corresponding electron beam to a desiredposition on the substrate as a target object. Further, the each of theplurality of multiple-beam sets 12 includes a plurality of electrostaticor electromagnetic lens fields each to focusing the correspondingelectron beam on the target object. The multiple-beam cluster 16, themultiple-beam block 14, and the multiple-beam set 12 are examples of themulti-columns. As the substrate 101, for example, a semiconductorsubstrate (semiconductor wafer) coated with a resist, a mask substrateto which a resist is applied for transferring a mask pattern to asemiconductor wafer or the like is used. Further, the pattern writingchamber 102 is evacuated by a vacuum pump (not shown) and is controlledto have a vacuum environment lower than the atmospheric pressure. Theevacuation of an electron optical barrel is performed in units of themultiple-beam cluster 16 and if the evacuation of a target objectchamber storing the stage 105 on which a plurality of substrates 101 isplaced is carried out collectively in the entire system, the system canbe made smaller than when the evacuation is carried out collectively inthe entire electron optics.

The control system circuit 160 includes a control computer 110, a memory112, a deflection control circuit 130, a digital/analog conversion (DAC)amplifier 132, a lens control circuit 134, a stage drive circuit 139, apower supply circuit 170, relay circuits 180, 182, 184, 186, and storagedevices 140, 142 such as a magnetic disk drive. The control computer110, the memory 112, the deflection control circuit 130, the lenscontrol circuit 134, the stage drive circuit 139, the power supplycircuit 170, and the storage devices 140, 142 are connected to eachother via a bus (not shown). The DAC amplifier 132 and the relay circuit184 are connected to the deflection control circuit 130. The output ofthe DAC amplifier 132 is connected to the relay circuit 186. The powersupply circuit 170 is connected to the relay circuit 180. The lenscontrol circuit 134 is connected to the relay circuit 182. In FIG. 1,only one DAC amplifier 132 and one relay circuit 186 are shown, but asmany circuits as the number obtained by multiplying the number ofelectrodes of the deflector described below by the number of themultiple-beam sets 12 are arranged. Similarly, though only one relaycircuit of each relay circuit 180, 182, 184 is shown in FIG. 1, eachrelay circuit 180, 182, 184 is suitably arranged for each of themultiple-beam sets 12, for example. Each relay circuit 180, 182, 184,186 is suitably arranged in the pattern writing chamber 102. The othercontrol system circuits 160 may be arranged in a control chamber (notshown). The stage drive circuit 139 moves the stage 105.

In the control computer 110, a rasterization unit 50, a dose calculationunit 52, a beam irradiation time data processing unit 54, and a patternwriting control unit 56 are arranged. Each “ . . . unit” such as therasterization unit 50, the dose calculation unit 52, the beamirradiation time data processing unit 54, and the pattern writingcontrol unit 56 has a processing circuit. Such processing circuitsinclude, for example, electric circuits, computers, processors, circuitsubstrates, quantum circuits, or semiconductor devices. Each “ . . .unit” may use a common processing circuit (the same processing circuit)or different processing circuits (separate processing circuits).Information input into or output from the rasterization unit 50, thedose calculation unit 52, the beam irradiation time data processing unit54, and the pattern writing control unit 56 and information duringoperation are stored in the memory 112 each time.

In addition, pattern writing data is input from outside the lithographyapparatus 100 and stored in the storage device 140. Normally,information on a plurality of graphic patterns to be written is definedin the pattern writing data. More specifically, a graphic code,coordinates, size and the like are defined for each graphic pattern.Alternatively, a graphic code, each vertex coordinate and the like aredefined for each graphic pattern.

Here, in FIG. 1, only the configuration needed to describe the firstembodiment is shown. Other configurations normally needed for thelithography apparatus 100 may also be included.

FIGS. 2A to 2C are diagrams showing an example of a system configurationof a multiple-beam cluster according to the first embodiment. In theexample of FIG. 2A, one multiple-beam set 12 is formed of 3×3 electronbeam columns 10 a, 10 b, 10 c, . . . arranged in the x and y directions(lengthwise and crosswise). In each of the electron beam columns 10, forexample, a cylindrical column (electron optical barrel) is arranged in aframe having a square cross section. Then, in the multiple-beam set 12,the 3×3 electron beam columns 10 a, 10 b, 10 c, . . . are suitablyconfigured to be put together and fitted into a frame (not shown) to beunitized. Then, in the example of FIG. 2B, one multiple-beam block 14 isconstructed of 3×3 multiple-beam sets 12 a, 12 b, 12 c, . . . arrangedin the x and y directions (lengthwise and crosswise). In themultiple-beam block 14, these 3×3 multiple-beam sets 12 a, b, c, . . .are suitably configured to be put together and fitted into a frame (notshown) to be unitized. In the example of FIG. 2C, one multiple-beamcluster 16 is constructed of 2×2 multiple-beam blocks 14 a, 14 b,arranged in the x and y directions (lengthwise and crosswise). In themultiple-beam cluster 16, it is preferable that these 2×2 multiple-beamblocks 14 a, 14 b, . . . are suitably configured to be put together andfitted into a frame (not shown) to be unitized. In the example of FIGS.2A to 2C, it is possible to irradiate 324 multiple beams by onemultiple-beam cluster 16. The system configuration of the multiple-beamcluster 16 is not limited thereto.

It is also suitable to provide a reflection electron detector or a Zsensor mechanism using an optical lever in the frame. In addition, awater cooling pipe for temperature adjustment may also be provided inthe frame.

FIG. 3 is a diagram showing another example of the system configurationof a multiple-beam block according to the first embodiment.

FIG. 4 is a diagram showing another example of the system configurationof the multiple-beam cluster according to the first embodiment. In theexamples of FIGS. 3 and 4, one multiple-beam set 12 is constructed of,for example, 19 electron beam columns 10 a, 10 b, 10 c, . . . arrangedin a honeycomb shape. In each of the electron beam columns 10, forexample, a cylindrical column (electron optical barrel) is arranged in aframe having a regular hexagonal cross section. Then, in themultiple-beam set 12, these 19 electron beam columns 10 a, 10 b, 10 c, .. . are suitably configured to be put together and fitted into a framehaving a regular hexagonal cross section to be unitized. Then, onemultiple-beam block 14 is constructed of, for example, 19 multiple-beamsets 12 a, 12 b, 12 c, . . . arranged in a honeycomb shape. Then, in themultiple-beam block 14, these 19 multiple-beam sets 12 a, 12 b, 12 c, .. . are suitably configured to be put together and fitted into a framehaving a regular hexagonal cross section to be unitized. Then, onemultiple-beam cluster 16 is constructed of, for example, 19multiple-beam blocks 14 a, 14 b, 14 c, . . . arranged in a honeycombshape. Then, in the multiple-beam cluster 16, these 19 multiple-beamblocks 14 a, 14 b, 14 c, . . . are suitably configured to be puttogether and fitted into a frame having a regular hexagonal crosssection to be unitized. By arranging in the honeycomb structure,unnecessary gaps can be reduced and the number of arrays of the electronbeam columns 10 per unit area can be increased (the electron beam column10 can be densely arranged). In other words, the number of multiple beambeams per unit area can be increased (multiple beams can be denselyarranged). In the examples of FIGS. 3 and 4, it is possible to irradiate6859 multiple beams by one multiple-beam cluster 16.

FIG. 5 is a diagram showing another example of the system configurationof a multiple-beam set according to the first embodiment. In the exampleof FIG. 5, one multiple-beam set 12 is constructed by, for example, 24electron beam columns 10 a, 10 b, 10 c, . . . arranged to form regularhexagons by combining sides of a plurality of regular triangles. In eachof the electron beam columns 10, for example, a cylindrical column(electron optical barrel) is arranged in a frame having a regulartriangular cross section. Then, in the multiple-beam set 12, these 24electron beam columns 10 a, 10 b, 10 c, . . . are suitably configured tobe put together and fitted into a frame having a regular hexagonal crosssection to be unitized. The system configurations of the multiple-beamblock 14 and the multiple-beam cluster 16 may be the same as in FIGS. 3and 4. In the example of FIG. 5, it is possible to irradiate 8664multiple beams by one multiple-beam cluster 16.

FIG. 6 is a diagram showing still another example of the systemconfiguration of the multiple-beam set according to the firstembodiment. In the example of FIG. 6, one multiple-beam set 12 isconstructed by, for example, nine electron beam columns 10 a, 10 b, 10c, . . . arranged to form regular triangles by combining sides of aplurality of regular triangles. In each of the electron beam columns 10,for example, a cylindrical column (electron optical barrel) is arrangedin a frame having a regular triangular cross section. Then, in themultiple-beam set 12, these nine electron beam columns 10 a, 10 b, 10 c,. . . are suitably configured to be put together and fitted into a framehaving a regular triangular cross section to be unitized. For the systemconfigurations of the multiple-beam block 14 and the multiple-beamcluster 16, as shown in FIG. 6, a plurality of triangles may be arrangedso as to form a regular triangle by combining sides of the regulartriangles. In the example of FIG. 6, it is possible to irradiate, forexample, 729 multiple beams by one multiple-beam cluster 16.

FIG. 7 is a diagram showing still another example of the systemconfiguration of the multiple-beam set according to the firstembodiment. In the example of FIG. 7, one multiple-beam set 12 isconstructed by, for example, eight electron beam columns 10 a, 10 b, 10c, . . . arranged to form parallelograms by combining sides of aplurality of regular triangles. In each of the electron beam columns 10,for example, a cylindrical column (electron optical barrel) is arrangedin a frame having a regular triangular cross section. Then, in themultiple-beam set 12, these eight electron beam columns 10 a, 10 b, 10c, . . . are suitably configured to be put together and fitted into aframe having a parallelogram cross section to be unitized. For thesystem configurations of the multiple-beam block 14 and themultiple-beam cluster 16, a plurality of parallelograms may be arrangedso as to form a parallelogram by combining sides of the parallelograms.

In any of the arrangement configurations of FIG. 2A to FIG. 2C to FIG.7, one unitized multiple-beam set 12 is constructed of a plurality ofelectron beam columns 10 a, 10 b, 10 c, . . . . Similarly, one unitizedmultiple-beam block 14 is constructed of a plurality of multiple-beamsets 12 a, 12 b, 12 c, . . . . Similarly, one unitized multiple-beamcluster 16 is constructed of a plurality of multiple-beam blocks 14 a,14 b, . . . . By dividing the configuration into a plurality of unitizedlayers, units can be easily combined according to the level of thenumber of beams to be added. In other words, the number of beams of themultiple beam can be easily increased according to the level of theadditional number.

FIG. 8 is a diagram showing an example of an internal configuration ofan electron beam column according to the first embodiment. In each ofthe electron beam columns 10 a, 10 b, 10 c, . . . , an electron gunassembly 201, a limiting aperture plate substrate 202, a blankingdeflector 204, an electrostatic lens 205, a limiting aperture platesubstrate 206, an electrostatic lens 208, and an objective deflector 209are arranged. The example of FIG. 8 shows a case where the electron beamcolumns 10 a, 10 b, 10 c, . . . are individually configured by theelectron gun assembly 201, the limiting aperture plate substrate 202,the blanking deflector 204, the electrostatic lens 205, the limitingaperture plate substrate 206, the electrostatic lens 208, and theobjective deflector 209 being arranged in, for example, one cylindricalelectron optical barrel (column). As shown in the example of FIG. 8, theelectron gun assembly 201 serving as an independent irradiation sourcefor irradiating an electron beam is individually arranged in each of theelectron beam columns 10 a, 10 b, 10 c, . . . . Further, in each of theelectron beam columns 10 a, 10 b, 10 c, . . . , the objective deflector209 that deflects the corresponding electron beam to a desired positionon the substrate 101 serving as a target object is individuallyarranged. Therefore, each of the multiple-beam sets 12 includes aplurality of electron gun assemblies 201 that irradiate independentelectron beams and a plurality of objective deflectors 209 that deflectthe corresponding electron beams to desired positions on the substrate101. Further, in the example of FIG. 8, a plurality of electrostaticlenses 205, 208 that guide the corresponding electron beams so as tofocus on the substrate 101 are individually arranged in each of theelectron beam columns 10 a, 10 b, 10 c, . . . it is assumed that thediameter of a region occupied by one electron beam column 10 is, forexample, about 2 mm, and the distance from the tip of the electron gunassembly to the surface of the substrate 101 is, for example, about 20mm. The acceleration voltage is, for example, 3 kV. Lenses with such asmall structure can be manufactured by using MEMS technology or micromachining technology.

If it is assumed here that the stage moving direction is the xdirection, when the minimum value of a deflection region in the ydirection of a certain electron beam column 10 is y1, the maximum valuethereof is y2, and the range in the y direction defined by y1≤y≤y2 isdefined as wy, the y directional range covered by an entire range Wytotobtained by combining all wy is such that at least the range in the ydirection where a pattern is to be written is covered and there is nogap. This makes it possible to expose the entire region where a patternis to be written even by moving the stage only in the x direction.

In each of the electron beam columns 10 a, 10 b, 10 c, . . . , anelectron beam 20 emitted from the electron gun assembly 201 (emissionsource) illuminates the limiting aperture plate substrate 202 as awhole. A rectangular or circular hole (opening) is formed in the centerof the limiting aperture plate substrate 202, and a portion of theelectron beam 20 passes through such a hole, whereby a beam shape isformed. In this manner, a common voltage is applied to the plurality ofelectron gun assemblies 201 in the multiple-beam set 12 via the relaycircuit 180 under the control of the power supply circuit 170. In theexample of FIG. 8, for example, a micro field electron source (fieldemission type electron gun assembly) is used as the electron gunassembly 201. In the micro field electron source, an electron groupemitted from an emitter (not shown) is accelerated by application of, inaddition to the application of an acceleration voltage from the powersupply circuit 170 to between the emitter and an extraction electrode(anode), a voltage of an extraction electrode (Wehnelt) before beingemitted as the electron beam 20. Because a common voltage is applied tothe plurality of electron gun assemblies 201 from the same power supplycircuit 170 (or the same relay circuit 180), the numbers of power supplysystems and control systems can be greatly reduced as compared with thenumber of beams. However, the present embodiment is not limited to sucha case. By controlling the voltage applied to the extraction electrode(Wehnelt) of each of the electron gun assemblies 201, the currentemitted from the emitter can be controlled. Further, the electron gunassemblies 201 may be ON/OFF controlled individually. Unlike the casewhere multiple beams are formed from a beam emitted from one electrongun assembly, the electron gun assembly 201 of each of the electronbeams 20 is different and thus, an increase in output of each of theelectron gun assemblies 201 is not dispersed to a plurality of beams sothat the amount of current per beam can be greatly increased. Therefore,if the amount of current from each of the electron aun assemblies 201 isincreased, the current amount of the entire multiple beams can begreatly increased. Therefore, the amount of current per unit areaincreases and the dose amount per unit time can be increasedcorrespondingly. Therefore, the beam irradiation time for giving thedose amount necessary for resolving the resist on the substrate 101 canbe greatly shortened, and the throughput can be improved.

The electron beam 20 having passed through the hole of the limitingaperture plate substrate 202 passes through the blanking deflector 204.The blanking deflector 204 individually deflects (deflects by blanking)a passing electron beam 20. The electron beam 20 that has not beendeflected as beam ON by the blanking deflector 204 is reduced by theelectrostatic lens 205 and advances toward the center hole formed in thelimiting aperture plate substrate 206. Here, the electron beam 20(dotted line) deflected so as to be in a beam OFF state by the blankingdeflector 204 deviates from the center hole of the limiting apertureplate substrate 206 and is shielded by the limiting aperture platesubstrate 206. On the other hand, the multiple electron beams 20 notdeflected by the blanking deflector 204 pass, as shown in FIG. 8,through the center hole of the limiting aperture plate substrate 206.Blanking control is performed by ON/OFF of the individual blankingmechanism (individual ON/OFF mechanism) constructed of the blankingdeflector 204 and the limiting aperture plate substrate 206 to controlON/OFF of the beam. Then, a beam for one shot is formed by a beam formedbetween beam ON and beam OFF and having passed through the limitingaperture plate substrate 206. In this way, a plurality of individualblanking mechanisms (individual ON/OFF mechanisms) in the multiple-beamset 12 is controlled by the deflection control circuit 130 toindividually turn ON/OFF the beam irradiated from a correspondingelectron gun assembly 201 as an irradiation source via the relay circuit184. Therefore, in each layer of the multiple-beam cluster 16, themultiple-beam block 14, and the multiple-beam set 12, each beam isindependently ON/OFF-controlled individually.

The electron beam 20 having passed through the limiting aperture platesubstrate 206 is focused on the substrate 101 by the electrostatic lens208 as an objective lens to become a pattern image of a desiredreduction ratio. Then, the electron beam 20 having passed through thelimiting aperture plate substrate 206 is deflected by the objectivedeflector 209 and a desired irradiation position on the substrate 101 isirradiated with the electron beam 20. In FIG. 8, in order to suppress anincrease in deflection aberration, an example is shown in whichtwo-stage deflection with two stages of deflectors is adopted.

FIG. 9 is a sectional view showing an example of an electrostatic lensaccording to the first embodiment. One electrostatic lens 205 (or 208)is constructed of three-stage disc-like electrodes 17, 18, and 19 havinga central opening. A ground potential is applied to the upper and lowerelectrodes 17 and 19, and the intensity of lens action for refractingelectrons is adjusted by adjusting the potential of the electrode 18 inthe center. In the example of FIG. 8, an electrostatic lens is used forreduction, projection, and objective lens, but the present embodiment isnot limited thereto. An electromagnetic lens may be arranged.Alternatively, a combination of an electrostatic lens and anelectromagnetic lens may also be arranged. In the example of FIG. 8,each of the electrostatic lenses 205 arranged in the same multiple-beamset 12 is suitably controlled commonly via the relay circuit 182 underthe control of the lens control circuit 134. Similarly, each of theelectrostatic lenses 208 arranged in the same multiple-beam set 12 issuitably controlled commonly via the relay circuit 182 under the controlof the lens control circuit 134. With such a configuration, eachelectrostatic lens of the plurality of electron beam columns 10 a, 10 b,10 c, . . . in one multiple-beam set 12 can be controlled bydistributing a common signal. Therefore, regardless of the number of theelectron beam columns 10 constituting the multiple-beam set 12, thecontrol system can be simplified.

Especially when there is a distribution in the target object surfaceheight, if the size of the area covered by the multiple-beam set issmaller than the width of the area in which one focus condition of thedistribution of the target object surface height variation correction isallowed, the correction amount for the focus adjustment of themultiple-beam set may be common. Also when the dynamic focus correctionis performed to change the potential distribution of the electrostaticlens electrode so that the blur of the electron beam on the targetobject surface becomes smaller in response to the target object surfaceheight, it is possible to reduce the control power supply for dynamicfocus correction by using a common power supply in the multiple-beamset.

FIG. 10 is a sectional view showing another example of the electrostaticlens according to the first embodiment. As shown in FIG. 10,electrostatic lenses can be used in multiple stages. This is effectivefor reducing the applied voltage. The same voltage can be applied toelectrodes 18, 18 b, or different voltage outputs can be connected toapply different voltages. The number of stages can be further increased.The ground potential is applied to an electrode 17 b.

FIG. 11 is a top view showing an example of the relationship betweenobjective deflectors and deflection amplifiers according to the firstembodiment. The example of FIG. 11 shows a case where the objectivedeflector 209 is constructed of, for example, eight electrodes 209-1 to209-8. By adjusting the potentials applied to the electrodes 209-1 to209-8, it is possible to deflect the electron beam 20 passing throughthe central portion surrounded by the eight electrodes 209-1 to 209-8.In the example of FIG. 11, under the control of the deflection controlcircuit 130, each of the objective deflectors 209 arranged in the samemultiple-beam set 12 is controlled in common via the relay circuit 186using the output from the common DAC amplifier 132. More specifically,for example, the potential as output of the same DAC amplifier 132-1distributed by the same relay circuit 186-1 is applied to electrodes209-1 of the objective deflectors 209 a, 209 b, arranged in the samemultiple-beam set 12. Similarly, the potential as output of the same DACamplifier 132-2 distributed by the same relay circuit 186-2 is appliedto electrodes 209-2 of the objective deflectors 209 a, 209 b, arrangedin the same multiple-beam set 12. Similarly, the potential as output ofthe same DAC amplifier 132-3 distributed by the same relay circuit 186-3is applied to electrodes 209-3 of the objective deflectors 209 a, 209 b,arranged in the same multiple-beam set 12. Similarly, the potential asoutput of the same DAC amplifier 132-4 distributed by the same relaycircuit 186-4 is applied to electrodes 209-4 of the objective deflectors209 a, 209 b, arranged in the same multiple-beam set 12. Similarly, thepotential as output of the same DAC amplifier 132-5 distributed by thesame relay circuit 186-5 is applied to electrodes 209-5 of the objectivedeflectors 209 a, 209 b, arranged in the same multiple-beam set 12.Similarly, the potential as output of the same DAC amplifier 132-6distributed by the same relay circuit 186-6 is applied to electrodes209-6 of the objective deflectors 209 a, 209 b, arranged in the samemultiple-beam set 12. Similarly, the potential as output of the same DACamplifier 132-7 distributed by the same relay circuit 186-7 is appliedto electrodes 209-7 of the objective deflectors 209 a, 209 b, arrangedin the same multiple-beam set 12. Similarly, the potential as output ofthe same DAC amplifier 132-8 distributed by the same relay circuit 186-8is applied to electrodes 209-8 of the objective deflectors 209 a, 209 b,arranged in the same multiple-beam set 12. In this manner, a pluralityof common DAC amplifiers 132, which are common deflection amplifiersarranged for each of the multiple-beam sets 12, controls a plurality ofobjective deflectors 209 arranged in the same multiple-beam set 12 incommon. Therefore, regardless of the number of the electron beam columns10 constituting the multiple-beam set 12, control can be exercised bythe same number of deflection amplifiers as the number of electrodes ofthe objective deflectors 209 constituting one electron beam column 10 inthe multiple-beam set 12. Therefore, when one objective deflector 209 isconstructed of, for example, eight electrodes, eight DAC amplifiers 132are required for each beam, but when, for example, 1800 beams areirradiated at a time as multiple beams, a situation where 14400 DACamplifiers 132 are required and the control of the 14400 DAC amplifiers132 is needed as in the past can be avoided. When the multiple-beam set12 is constructed of nine electron beam columns 10 and, for example,1800 beams irradiated at a time as multiple beams, 1600 DAC amplifiers132 are adequate and the control of the 1600 DAC amplifiers 132 isadequate. If the number of the electron beam columns 10 constituting themultiple-beam set 12 increases, the number of the DAC amplifiers 132 andthe number of the DAC amplifier 132 to be controlled can be furtherreduced.

In addition, it is possible to arrange a deflector for alignment andastigmatism correction for individual beams so that the trajectory canbe finely adjusted. Such an individual alignment deflector is basicallystatic and do not deflect during pattern writing operation so that thecircuit can be greatly simplified.

Similarly, it is possible to provide an electrostatic lens for fineadjustment of the focal point. This is also basically static and thevoltage is low so the circuit can be simplified.

FIG. 12 is a diagram showing an example of a plurality of chip regionsformed on a semiconductor substrate according to the first embodiment.In FIG. 12, when the substrate 101 is a semiconductor substrate (wafer),a plurality of chip (wafer die) regions 332 is provided in atwo-dimensional array in a pattern writing region 330 of thesemiconductor substrate (wafer). In each of the chip regions 332, thesame pattern for one chip is directly written by the lithographyapparatus 100 without going through a mask pattern. In the example ofFIG. 12, each of the chip regions 332 is divided into, for example, aplurality of small regions 33 in a two-dimensional shape of m₂ columnsin the width direction (x direction)×n₂ tiers in the length direction (ydirection) (m₂ and n₂ are integers of 2 or greater). Each of the smallregions 33 is further decomposed into pixels. The position of each pixeland the dose (beam irradiation time) are defined as beam irradiationtime data. The plurality of multiple-beam sets 12 respectively writesdifferent one or more of exposure pixel groups on the same substrate101.

Here, in the multiple-beam set for writing the vicinity of the boundaryof the substrate 101, there is a case in which different electron beamsincluded in the same multiple-beam set may be respectively irradiated todifferent substrates. Further, in the electron beam column without thepixel of the exposure target, the electron beam is blanked (in abeam-off state) while there is no exposure target.

In addition, an exposure pixel group to be exposed by a differentmultiple-beam set 12 is arranged between exposure pixel groups exposedby one multiple-beam set 12. Then, pattern writing processing of thesubstrate 101 is completed by the substrate 101 passes throughirradiable regions of the plurality of multiple-beam sets 12. A specificoperation is as described below.

Pattern writing is performed while continuously moving the stage 105. Inthe meantime, while one corresponding pixel is irradiated with eachelectron beam, the deflector 209 is used to deflect the electron beamaccording to the movement of the stage 105 so that the irradiationposition of each electron beam is on the same pixel without deviatingfrom the irradiated pixel on the surface of the substrate 101. This iscalled stage tracking. Here, the stage position information isdetermined by using the stage position measuring mechanism 138. Thestage tracking is performed within a range not exceeding a given maximumdeflection amount, and after the stage 105 moves a certain distance, thedeflection position is returned to the next irradiation position nearthe initial deflection position. The above is repeated to write apattern. The stage tracking may be configured so as to return to thevicinity of the initial deflection position every time one pixel isirradiated with an electron beam or to return to the next irradiationposition near the initial deflection position after irradiating aplurality of pixels with an electron beam. The dose of an electron beamto each pixel is adjusted by independently adjusting the beamirradiation time of the beam to the substrate 101 surface by using ablanking means of each beam. Also, while moving between pixels, ablanking operation is performed so that all beams do not reach thetarget object surface. Because the stage moves continuously, control isexercised so that different pixels in the same small region areirradiated with electron beams of different multiple-beam blocks 14 andwhen the substrate 101 passes downstream of all multi-clusters 16, allpixels on the substrate 101 are irradiated with an electron beam of apredetermined dose. In other words, there is a portion exposed to beamsof the same multiple-beam block 14 among the pixel array within a smallregion, and there is a portion exposed to beams of differentmultiple-beam blocks 14. In the following, for the sake of simplicity,the time needed to turn off a beam to return the deflection to itsoriginal is ignored. Also, the effect of the width of a frame used tofix the multiple-beam set 12 and the multiple-beam block 14 is ignored.

A case where all pixels with 10 nm pitches are exposed to an electronbeam by assuming that, for example, one pixel corresponds to 10 nmsquare is considered. When the electron beam columns 10 capable ofirradiating one pixel region with one electron beam are arranged in asquare lattice as shown in FIG. 2A to FIG. 2C and the interval betweenthe electron beam columns 10 is 2 mm, 4×10{circumflex over ( )}10 pixelsare included in a region of 2 mm square surrounded by four adjacentelectron beam columns 10. In reality, the current distribution of anelectron beam is not localized within 10 nm square and follows, forexample, a Gaussian distribution, and about 80% of the current ispresent within 10 nm square. However, in order to simplify thedescription, the current is approximated as being localized within 10 nmsquare. The small region size is assumed to be 2 mm. A deflection regionis assumed to be 10 μm square. Now, it is assumed that the stage speedto 10 mm/s, the effective current density (current density when thetotal current uniformly flows through 10 nm square) is 500 A/cm², andthe resist sensitivity is 50 uC/cm². When written as single patternwriting, the beam irradiation time for one pixel is 100 ns. In themeantime, the stage 105 moves by 1 nm.

FIG. 13 is a diagram illustrating an example of a pattern writingprocedure according to the first embodiment.

FIG. 14 is a diagram illustrating an example of the pattern writingprocedure according to the first embodiment. As shown in FIGS. 13 and14, while continuously moving the stage in the −x direction, thex-direction coordinate on the target object surface of an electron beamis fixed by deflection and then exposure is performed and after onepixel exposure, the electron beam is moved to the adjacent pixel in they direction on the target object surface and exposure is performed, andthis is continuously performed with the width of 10 μm. While 1,000pixels aligned in the y direction to a width of 10 μm is exposed, thestage 105 moves by 1000×1 nm=1 μm in the −x direction. In the meantime,the electron beam is also deflected by 1 μm in the −x direction. Next,the electron beam is deflected by 1 μm in the x direction to return tothe original x direction and y direction deflection position in thecolumn to repeat the exposure. At this point, if the deflection positionis not returned in the y direction, the deflection in the y directionduring the next exposure can be made in the opposite direction to theprevious exposure sequence.

The number of pixels included in the region of 10 μm×2 mm is2×10{circumflex over ( )}8, and the time for the stage to move 2 mm is0.2 sec. During this period, the number of pixels that can be irradiatedis 2,000,000. Therefore, one deflection width region of the same smallregion is made to be irradiated with 2×10{circumflex over( )}8/2×10{circumflex over ( )}6=100 different electron beams. Further,2 mm/10 um=200 rows exist in a direction perpendicular to the stageadvancing direction. Therefore, in the simplest model, it is necessaryto irradiate 4×10{circumflex over ( )}10 pixels in the 2 mm×2 mm regionwith 100×200=20,000 different electron beams. Considering that 300 mmwidth is filled in this way, 20,000×300/2=3,000,000 electron beams areneeded. At this point, it is necessary to arrange 150 rows of electronbeams in the lateral direction and 200×100=20,000 rows of electron beamsin the longitudinal direction.

At this point, it is not necessary to arrange 20,000 electron beamcolumns 10 in one 2-mm wide stripe. What is necessary is that allexposure pixels on the surface of the substrate 101 can be exposed, andan offset may be added to the position in a direction perpendicular tothe stage advancing direction as appropriate under the conditionsatisfying the above situation. In this case, it is necessary toincrease the beam at the extreme end by one row, but the influence onthe entire system is small. Conversely, considering a positional errorof the installation of the substrate 101, the system desirably has asmany electron beams as possible that can be made equal to or wider thanthe installation error of the substrate 101 as an exposable width of theelectron beam.

In the simplest configuration that satisfies the condition, an electronbeam array of 3,000,000 electron beams with a width of about 300 mm anda length of about 40 m is needed.

In another more realistic configuration, instead of arranging 20,000rows of electron beams in the stage advancing direction, a beam array ofa smaller size, for example, 2,000 rows is arranged in the advancingdirection and the same effect as passing the 20,000 rows is effectivelyobtained by causing the same substrate 101 to pass below the samemultiple-beam cluster 16 repeatedly 10 times or more. The length of abeam array of 2000 rows in the stage advancing direction is about 4 m,which is much larger than the size of the substrate 101.Correspondingly, the number of the substrates 101 (for example, 300 mmwafers) having a diameter of, for example, 30 cm to be mounted on thelithography apparatus at a time is set to 14 or more (4 m/30 cm≈) from13.

In order to implement such an operation, a plurality of wafers isarranged in a row on the stage and then, two methods of (1) the stage ismade to reciprocate and (2) the stage is made to circulate and thewafers are circumferentially arranged can be considered. In both cases,by moving the wafer by the necessary moving distance, all pixels aremade to be irradiated with an electron beam. Further, in (2), as anexample of the circulating motion of the stage, making the stage operatein a circular shape and operate in a racetrack shape can be considered.By mounting a plurality of wafers and correspondingly operating aplurality of clusters, the effective current amount of the entire systemcan be increased so that the exposure time per wafer can be shortened.In the example described above, if the exposure is completed in onepass, ideally, the pattern writing time per wafer is calculated as 300mm/10 mm/s to 30 sec. However, considering the dead time, the stagemoving speed is slightly lower than the above value, so the patternwriting time is longer than the above value. When multiple rotations areperformed, the required exposure time becomes longer approximately inproportion to the number of rotations.

For each beam, the deflection of each electron beam uses the samecontrol voltage in at least one multiple-beam set 12 and only theexposure time is independently controlled. Accordingly, the number ofdeflection amplifiers required for deflection control can be greatlyreduced. Also, the input/output unit can be simplified.

In the above example, the pitch of the exposure pixels is set to 10 nm,but it is also possible to make the pitch smaller. For example, exposurecan be performed by performing double pattern writing in which theexposure pixel is 5 nm square and the electron beam is shifted by 5 nm.Alternatively, the exposure pitch can be increased.

In the above discussion, the conditions for the wafer dimensions of 300mm square are considered to be given. Actually, the wafer shape isgenerally round and so the number of beams required in the x directiondecreases at a position away from the center of the wafer in the ydirection. Therefore, the shape of the beam cluster is not rectangular,and the multiple-beam block 14 may be arranged so that the width in thex direction decreases in stages with an increasing distance from thewafer center in the y direction. In this way, the shape of the clustercan be changed according to the shape of the target object. Further, forexample, as shown in FIG. 25, when a plurality of parallelograms havingthe same shape and including a plurality of multiple-beam blocks 14 (forexample, eight multiple-beam blocks 14) are connected at the upper sideof the drawing, it is also possible to arrange the parallelograms sothat the sides of parallelogram pairs are in contact with each other andthe directions of the sides of other parallelogram pairs are staggered.Also in this configuration, the width in the x direction can be madesubstantially uniform.

In the pattern writing method described above, by continuously movingthe stage during pattern writing and irradiating a small region withelectron beams belonging to different multiple-beam sets 12,multiple-beam blocks 14, and multiple-beam clusters 16, even when thebeam pitch is much larger than the pixel size, pattern writing can beperformed at high speed. Further, a plurality of multiple-beam clusters16 can be arranged beyond one target object area and so, a beam currentof the entire system can be increased and the pattern writing time perwafer can be drastically shortened.

In order to make the stage movement in the y direction unnecessary, whenthe electron beam pitch is 2 mm and the deflection width is 10 μm, themovement can be made unnecessary if there are 2 mm/10 μm=100 rows ofstage advancing direction beams. Therefore, using one set of themultiple-beam clusters 16 of 150 rows×100 rows as the minimum unit, awafer can be exposed while reciprocating the stage. In this case, if thenumber of wafers is one, the ratio of the presence of unexposed regionsof the wafer is high during pattern writing and so the pattern writingefficiency is low and therefore, it is desirable to always operate anelectron beam by mounting two wafers on the stage.

In the above discussion, an ideal apparatus has been described, but inpractice, an error occurs in the pattern writing position due to variousfactors and beam exposure regions do not densely align so that gaps areformed or overlapping arises. Further, there is a case in which adefective electron beam column which cannot obtain electron beamemission from the electron gun assembly is included. When there is areproducible error in the electron beam irradiation position, theoccurrence of defects can be prevented by, for example, increasing themultiplicity of beam exposure so that the beam can be exposed to allpixels and then reallocating the exposure amount. For example, ifeight-fold pattern writing is adopted and an extra time of about 15% isallocated to each exposure time, maximal one non-exposure can be made upby the seven remaining exposures. The multiple pattern writing method isalso effective to suppress the influence of errors that are notreproducible. Further, when the number of electron beam columns isredundant so that a part of the electron beam columns is generallyblanked (in a beam-off state), the pixel position to be irradiated bythe defective electron beam column can be exposed only at the exposureenabled timing.

An example of a data processing method when pattern drawing on a waferis performed by a lithography apparatus including a plurality ofmultiple-beam clusters 16 will be described below.

First, when pattern writing is performed using a pattern writing systemincluding the plurality of multiple-beam clusters 16, for each beam, thepixel to be exposed and the contribution to the pixel are determined.

Generally, the deflection position is adjusted so as to coincide withthe pixel to be exposed, but it is difficult to make the pixel to beexposed coincide with the beam irradiation position for all beamsbelonging to one multiple-beam set 12 due to individual differences ofthe deflector. When the beam center and the pixel center coincide witheach other, 1 is set and when it deviates, a real number is setaccording to the dose to the pixel. The real number is usually equal toor less than 1. Generally, if apparatus conditions do not change, theallocation is common to all pattern writing. This allocation work may bedone once.

Next, the exposure amount distribution on each wafer is determined basedon design data of LSI to be written on the wafer. When the same LSIpattern is arranged side by side on the wafer and written, the simplestmethod is to find the exposure amount distribution for one LSI andarrange the distribution according to the arrangement of the LSIpattern. Generally, the optimum exposure amount for suppressing theinfluence of process error changes depending on the location on thewafer even for the same LSI pattern. When this correction is needed, theexposure distribution including the correction is determined.

Next, the dose for each irradiation position of each beam is determinedfrom the relationship between the exposure amount distribution given toeach pixel and the previously determined contribution of each beam. Thiscalculation generally takes calculation time and so, the calculationtime is saved by appropriate approximations. When the deviation betweenthe beam irradiation position and the exposure pixel is small, patternwriting can be performed by making approximations that the beamirradiation position and the exposure pixel center coincide and further,making the dose coincide with the dose allocated to the exposure pixel.When the whole blur is a combination of a beam blur and a process blur,the entire blur due to one electron beam is larger than the exposurepixel in many cases and so, even in this case as well, the deviation ofthe obtained dose distribution from the desired dose distribution issmall.

Pattern writing is performed based on the beam irradiation time at eachirradiation position of each obtained beam.

When the gradation of the dose may be small, for example, eightgradations may be used for eight-fold pattern writing and there is noneed to consider the influence of a beam irradiation position error,switching whether or not to irradiate each beam is performed so that thebeam irradiation time of all beams to be irradiated can be made to bethe same. In this case, the dose control system can be greatlysimplified.

For example, it is conceivable to arrange 15 multiple-beam clusters 16of 150 rows×150 rows as a method of implementing a beam array of 2000rows or more in the advancing direction. Further, by constructing eachof the multiple-beam clusters 16 as, for example, the multiple-beamblocks 14 of 50 rows×50 rows and further, each of the multiple-beamblocks 14 as the multiple-beam sets 12 of 10 rows×10 rows, it isextremely effective from the viewpoint of the structure of the apparatusand maintenance to adopt a configuration in which each beam set, each ofthe multiple-beam blocks 14, and each of the multiple-beam clusters 16is removable from the main body system. It is desirable to provide acontact point of a deflection signal in the connecting portion of themultiple-beam set 12 to the multiple-beam block 14 by setting thedeflection operation as a block unit operation. Also, it is possible tofine-tune the control of the electrostatic lens by adopting themultiple-beam set 12 as the unit of control.

By adopting a structure having a hierarchy like this, it becomes easy toexpand the system, and the size and the number of the multiple-beamclusters 16 are changed according to the desired target object size andexposure time.

FIG. 15 is a diagram showing an example of a pattern writing techniquewhen a pattern is written in a small region in the chip region in thefirst embodiment with the multiple-beam set. The example of FIG. 15shows a case where the multiple-beam set 12 is constructed of, forexample, 3×3 electron beam columns 10. Thus, the multiple-beam set 12can irradiate, for example, 3×3 multiple beams. In the example of FIG.15, the size in the y direction of a small region 33 in the chip region332 is divided by the number of beams (9) of the multiple-beam set 12into a plurality of stripe regions in a strip form. Then, themultiple-beam image is rotated at an angle at which each of the electronbeams 20 of 3×3 multiple beams can take charge of one stripe region at atime. This can be implemented by arranging the phase of themultiple-beam set 12 at an angle with respect to the stage advancingdirection. Alternatively, beam groups each being three beams arranged inthe y direction may be arranged in parallel at equal pitches in the xdirection, and each beam group arranged in the x direction may bearranged to shift in order by the width of the stripe in the ydirection. FIG. 15 shows an example in which the width of each stripe iswithin the deflection width and the stage 105 is continuously moved, forexample, in the −x direction. Accordingly, the electron beams 20 a, 20b, 20 c, . . . write a pattern while raster-scanning the stripe regionin charge according to the movement of the stage 105. More specifically,it is sufficient to turn on the beam at the position where a pattern ispresent and to turn off the beam at the position where no pattern ispresent.

In FIG. 15, the position exposed to each beam is indicated by a solidline. Each electron beam is deflected in the −x direction according tothe moving speed of the stage and moves in the y direction aftercompletion of exposure of one pixel. After exposure of an edge pixel,each beam is deflected in the x direction to return to the originaldeflection position and resumes pattern writing. In this example, a casewhere the stage moves in the −x direction by the same distance as thestripe width when the exposure in the y direction is completed. On thetarget object surface, y-direction straight lines as the exposurestripes are aligned in the x direction at regular intervals. It shouldbe noted that this is an example, and it is not absolutely necessary forthe exposure regions to be arranged consecutively in the y direction. Aregion not covered with a line remains in the stripe region, indicatingthat the chip region 332 as a whole cannot be exposed while the stagepasses once. The exposure positions of beams of different multiple-beamsets 12 are made different from the exposure positions of othermultiple-beam sets 12, and the unexposed regions are exposed bysubsequent multiple-beam sets 12. Hereinafter, when the multiple-beamset 12 passes through a certain small region once, a set of pixelsexposed by a certain beam belonging to the multiple-beam set 12 iscalled an exposure pixel group belonging to the small region andcorresponding to the beam. By exposing all exposure pixel groups withinthe small region, all pixels within the small region are exposed. Theremay be an overlap of exposure pixel groups corresponding to differentbeams.

Also, in order to check the soundness of the system, it is desirable toprovide a beam measuring means outside a target object position on thestage. It is desirable to be able to measure the beam current, position,and beam blur of individual beams by the beam measuring means. Thesoundness of each electron beam can be checked by passing a measuringmeans installation region under the whole electron beams during exposureor before or after exposure. When a beam in which an abnormality occursis found, for example, a spare column that is not normally used isprovided and the emission of the electron beam from the column where theabnormality has occurred is stopped and supplemented by the spare columninstead. If the number of abnormal columns increases beyond a certainnumber, the system is stopped to replace the multiple-beam set 12including abnormal beams. The multiple-beam set 12 that has been removedis kept as a spare multiple-beam set 12 after the abnormal column isrepaired or replaced.

As a specific configuration of the beam measuring means, it issufficient to include a Faraday cup for current measurement, an openingtype mark for position measurement, and a Faraday cup with a knife edge.

FIG. 16 is a diagram illustrating an example of a method of performingcontinuous pattern writing on a plurality of substrates according to thefirst embodiment. In the example of FIG. 16, the stage 105 has aplurality of substrates 101 a, 101 b, 101 c, 101 d, 101 e arranged sideby side in the moving direction (−x direction). Then, by moving thestage 105 in the −x direction, the plurality of substrates 101 a, 101 b,101 c, 101 d, 101 e on the stage 105 can be moved in the −x direction.In the example of FIG. 16, the plurality of multiple-beam clusters 16 isarranged in the same direction as the moving direction of the pluralityof substrates 101 so that the plurality of substrates 101 sequentiallypasses through the irradiation region of each of the plurality ofmultiple-beam clusters 16. The multiple-beam clusters 16 write patternson mutually different substrates 101 at the same time. In other words,the plurality of multiple-beam sets 12 is arranged in the same directionas the moving direction of the plurality of substrates 101. In thisexample, there is a case in which the electron beam column included inthe adjacent multiple-beam clusters 16 may write different positions ofthe same substrate 101 or adjacent substrates 101. When the size of themultiple-beam cluster in the stage advancing direction is smaller thanthe substrate 101, there is a case in which three or more multiple-beamclusters 16 write the same substrate 101. Load-lock (L/L) chambersystems 300 a, 300 b for loading the substrate 101 into the patternwriting chamber 102 and unloading the substrate 101 out of the patternwriting chamber 102 are arranged in front and behind the movingdirection of the stage 105. The plurality of substrates 101 a, 101 b,101 c, 101 d, 101 e sequentially loaded from the L/L chamber system 300a to the stage 105 are sequentially moved in the −x direction inaccordance with the movement of the stage 105. Each beam belonging tothe multiple-beam clusters 16 a, 16 b, 16 c writes an exposure pixelgroup corresponding to each beam for each small region in each of thesubstrates 101 a, 101 b, 101 c, 101 d, 101 e by sequentially moving intoits irradiation region. By writing a pattern in this manner, exposure isgenerally performed by beams belonging to a plurality of multiple-beamclusters 16 for one small region. A plurality of multi-columnscontinuously writes a pattern on a plurality of substrates 101 while theplurality of substrates 101 moves in the moving direction. Then, thepattern writing processing of each of the substrates 101 is completed byeach of the substrates 101 passes through the irradiable region of theplurality of multi-columns (here, three multiple-beam clusters 16 a, 16b, 16 c). If exposure of all pixels is not completed in one movement,the stage is further reciprocated as many times as necessary to exposeall pixels. The substrate 101 on which the pattern writing processinghas been completed is sequentially unloaded from the pattern writingchamber 102 to the outside by the L/L chamber system 300 b. As describedabove, by configuring irradiation regions of the plurality ofmultiple-beam clusters 16 a, 16 b, 16 c aligned in the moving directionso that the plurality of substrates 101 passes therethroughcontinuously, the pattern writing processing is continuously performedand a large amount of semiconductor substrates can be manufactured. Inthe first embodiment, the size of the small region 33 is reducedregardless of the number of the chip regions 332 formed on one substrate101 and by adding the multiple-beam set 12 correspondingly, thethroughput can further be improved. Therefore, semiconductor wafers canbe mass-produced.

FIG. 17 is a diagram illustrating another example of the method ofperforming continuous pattern writing on the plurality of substratesaccording to the first embodiment. In the example of FIG. 17, the stage105 rotates (θ direction) about the center axis and a plurality ofsubstrates 101 a, 101 b, 101 c, 101 d, 101 e, 101 f is arranged side byside on a circulating track. Then, by rotating the stage 105, theplurality of substrates 101 a, 101 b, 101 c, 101 d, 101 e, 101 f on thestage 105 can continuously be moved along the circulating track. In theexample of FIG. 17, a plurality of multiple-beam clusters 16 is arrangedalong the circulating track of a plurality of substrates 101 so that theplurality of substrates 101 sequentially passes through the irradiationregions of each of the plurality of multiple-beam clusters 16. In otherwords, the plurality of multiple-beam sets 12 is arranged in the samedirection as the moving direction of the plurality of substrates 101.The L/L chamber system 300 a for loading each of the substrates 101 intothe pattern writing chamber 102 is arranged at one place on thecirculating track. Then, the L/L chamber system 300 b for unloading eachof the substrates 101 from the pattern writing chamber 102 is arrangedin front of the L/L chamber system 300 a by moving on the circulatingtrack. The plurality of substrates 101 a, 101 b, 101 c, 101 d, 101 e,101 f sequentially loaded from the L/L chamber system 300 a to the stage105 is sequentially moved on the circulating track in accordance withthe movement of the stage 105. Each beam belonging to the multiple-beamclusters 16 a, 16 b, 16 c, 16 d writes an exposure pixel groupcorresponding to each beam for each small region in each of thesubstrates 101 a, 101 b, 101 c, 101 d, 101 e, 101 f by sequentiallymoving into its irradiation region. In the example of FIG. 17, patternwriting processing of each of the substrates 101 is started from thelocation (predetermined location) of the multiple-beam cluster 16 a onthe circulating track and a plurality of multi-columns (here,multiple-beam clusters 16 a, 16 b, 16 c, 16 d) writes a pattern on theplurality of substrates 101 such that the pattern writing processing ofeach of the substrates 101 is completed before each of the substrates101 returns to a location (in front of the predetermined location) ofthe multiple-beam cluster 16 d by moving on the circulating track. Inother words, a plurality of multi-columns (here, four multiple-beamclusters 16 a, 16 b, 16 c, 16 d) writes a pattern on a plurality ofsubstrates so that the pattern writing processing of each of thesubstrates 101 is completed by the time when each of the substrates 101makes one turn on the circulating track. Further in other words, each ofthe plurality of multiple-beam clusters 16 writes a pattern on adifferent one of substrates 101 at the same time. By a pattern beingwritten by the multiple-beam clusters 16 a, 16 b, 16 c, 16 d in thismanner, exposure is generally performed by beams belonging to aplurality of multiple-beam clusters 16 for one small region. A pluralityof multi-columns continuously writes a pattern on a plurality ofsubstrates 101 while the plurality of substrates 101 moves in the movingdirection. Then, the pattern writing processing of each of thesubstrates 101 is completed by each of the substrates 101 passingthrough the irradiable region of the plurality of multi-columns (here,four multiple-beam clusters 16 a, 16 b, 16 c, 16 d). If exposure of allpixels is not completed in one rotation, the stage is further rotated asmany times as necessary to expose all pixels. In other words, theplurality of multiple-beam sets 12 writes a pattern on a plurality ofsubstrates 101 so that the pattern writing processing of each of thesubstrates 101 is completed by the time when each of the substrates 101makes one turn or a plurality of turns on the circulating track.

In a state where the plurality of substrates 101 is continuously movedin the predetermined direction, each multiple-beam set 12 sequentiallywrites a portion of the pattern on a different one or more of exposurepixel groups in a same small region on a same substrate 101. The smallregion is smaller than each die region 332 of a plurality of die regions332 to form a same pattern, and the plurality of die regions is providedon each substrate 101 of the plurality of substrates. The substrate 101on which the pattern writing processing has been completed issequentially unloaded from the pattern writing chamber 102 to theoutside by the L/L chamber system 300 b. As described above, byconfiguring irradiation regions of the plurality of multiple-beamclusters 16 a, 16 b, 16 c, 16 d aligned in the moving direction so thatthe plurality of substrates 101 passes therethrough continuously, thepattern writing processing is continuously performed and a large amountof semiconductor substrates can be manufactured. In the firstembodiment, the size of the small region 33 is reduced regardless of thenumber of the chip regions 332 formed on one substrate 101 and by addingthe multiple-beam set 12 correspondingly, the throughput can further beimproved. Therefore, semiconductor wafers can be mass-produced. Thenumber of pixels that can be exposed can be increased by makes aplurality of turns. At this point, it is desirable to suppress anincrease in exposure time by increase the rotation speed in accordancewith the number of turns.

FIG. 18 is a diagram illustrating still another example of the method ofperforming continuous pattern writing on the plurality of substratesaccording to the first embodiment. In the example of FIG. 17, the casewhere the L/L chamber systems 300 a, 300 b for loading/unloading thesubstrate 101 are arranged on the circulating track has been described,but the present embodiment is not limited thereto. In the example ofFIG. 18, the multiple-beam cluster 16 is arranged also in thearrangement locations of the L/L chamber system 300 a, 300 b forloading/unloading the substrate 101 on the circulating track. Thus, forexample, six multiple-beam clusters 16 a, 16 b, 16 c, 16 d, 16 e, 16 fcan be arranged on the same circulating track. The L/L chamber systems300 a, 300 b may be arranged at locations deviating from the circulatingtrack. Alternatively, six substrates 101 may first be loaded into theirradiatable regions of the six multiple-beam clusters 16 a, 16 b, 16 c,16 d, 16 e, 16 f and then, the stage 105 may be rotated. Then, patternwriting processing of each of the substrates 101 is started from themultiple-beam cluster (for example, the multiple-beam cluster 16 a)where each of the substrates 101 is first arranged and a plurality ofmulti-columns (here, multiple-beam clusters 16 a, 16 b, 16 c, 16 d, 16e, 16 f) writes a pattern on the plurality of substrates 101 such thatthe pattern writing processing of each of the substrates 101 iscompleted before each of the substrates 101 returns to the lastmultiple-beam cluster (for example, the multiple-beam cluster 16 f) bymoving on the circulating track. In other words, a plurality ofmulti-columns (here, six multiple-beam clusters 16 a, 16 b, 16 c, 16 d,16 e, 16 f) writes a pattern on the plurality of substrates 101 so thatthe pattern writing processing of each of the substrates 101 iscompleted by the time when each of the substrates 101 makes one turn onthe circulating track. Since the number of beams is larger than in theexample of FIG. 17, the throughput can be further improved. In this caseas well, when exposure of all pixels is not completed by one rotation,the stage is further rotated as many times as necessary to expose allpixels.

In the examples of FIGS. 17 and 18, the plurality of substrates 101moves along the circulating track, but each of the substrates 101 may beturned so as to rotate along with the movement on the circulating track.By rotating the substrate, it is possible to increase the types ofelectron beam columns that irradiate other pixels in the vicinity ofeach pixel on the substrate with an electron beam and the deviations ofelectron beam column characteristics in the apparatus can thereby beaveraged. In this case, since the phase of the arrangement of theelectron beam column and the arrangement of pixels on the substratechange with time, it is impossible to perform stage tracking in a strictsense, but the change of phase shifts is slower than the exposure timeof one pixel and so is negligible because the influence thereof on anexposure amount distribution error is small. Further, when allocatingthe exposure amount to each electron beam column, the accuracy of theexposure distribution control can further be increased by considering anerror of stage tracking due to the phase shift.

FIG. 19 is a diagram showing another example of the internalconfiguration of the electron beam column according to the firstembodiment. FIG. 19 shows an example in which the downstreamelectrostatic lens has two stages (207, 208) and the deflector 209 isarranged closer to the target object side than the downstreamelectrostatic lens. In the example of FIG. 19, a case where aphotoelectron source is used as the electron gun assembly 201 in each ofthe electron beam columns 10 a, 10 b, 10 c, . . . . Other configurationsare the same as in FIG. 8. It should be noted that the scales and thelike are not matched between FIG. 19 and FIG. 8. In the photoelectronsource, an acceleration voltage is applied from a high-voltage powersupply 172 in the power supply circuit 170 to between an emitter 23 ofwhich tip is pointed and an extraction electrode (anode) 22 and alsoultraviolet light is irradiated (excited) from an LED array circuit 174in the relay circuit 180 (or the power supply circuit 170) to the rearside of the emitter 23 to emit the electron beam 20 from the emitter 23.Because a supply voltage is applied to the plurality of electron gunassemblies 201 from the same power supply circuit 170 (or the same relaycircuit 180) and also ultraviolet light is irradiated from the samerelay circuit 180 (or the same power supply circuit 170), the numbers ofpower supply systems and control systems can be greatly reduced ascompared with the number of beams. However, the present embodiment isnot limited to such a case. The electron gun assemblies 201 may beON/OFF controlled individually. Unlike the case where multiple beams areformed from a beam emitted from one electron gun assembly, the electrongun assembly 201 of each of the electron beams 20 is different and thus,an increase in output of each of the electron gun assemblies 201 is notdispersed to a plurality of beams so that the amount of current per beamcan be greatly increased. Therefore, if the amount of current from eachof the electron gun assemblies 201 is increased, the current amount ofthe entire multiple beams can be greatly increased. Therefore, theamount of current per unit area increases and the dose amount per unittime can be increased correspondingly. Therefore, the beam irradiationtime for giving the dose amount necessary for resolving the resist onthe substrate 101 can be greatly shortened, and the throughput can beimproved.

FIG. 20 is a diagram showing still another example of the internalconfiguration of the electron beam column according to the firstembodiment. In the example of FIG. 20, a case where an MIM(metal-insulator-metal) type electron source is used as the electron gunassembly 201 in the electron beam columns 10 a, 10 b, 10 c, . . . .Other configurations are the same as in FIG. 8. It should be noted thatthe scales and the like are not matched between FIG. 20 and FIG. 8. Inthe MIM type electron source, an acceleration voltage is applied fromthe high-voltage power supply 172 in the power supply circuit 170 tobetween an emitter 21 and the extraction electrode (anode) 22 and also avoltage is applied from the high-voltage power supply 172 to between anupper electrode and a lower electrode (gate electrode) of the emitter 21to emit the electron beam 20 from the emitter 21. A gate pulse generator176 may be arranged between the high-voltage power supply 172 and thelower electrode (gate electrode) to output a pulse signal so that theelectron gun assemblies 201 may be ON/OFF controlled individually.Because a supply voltage is applied to the plurality of electron gunassemblies 201 from the same power supply circuit 170 (or the same relaycircuit 180), the numbers of power supply systems and control systemscan be greatly reduced as compared with the number of beams. Also,unlike the case where multiple beams are formed from a beam emitted fromone electron gun assembly, the electron gun assemblies 201 of therespective electron beams 20 are different and so an increase in outputof each of the electron gun assemblies 201 is not dispersed into aplurality of beams and the amount of current per beam can be greatlyincreased. Therefore, if the amount of current from each of the electrongun assemblies 201 is increased, the current amount of the entiremultiple beams can be greatly increased. Therefore, the amount ofcurrent per unit area increases and so the amount of dose per unit timecan be increased correspondingly, as in the case described above.

FIG. 21 is a diagram showing still another example of the internalconfiguration of the electron beam column according to the firstembodiment. In the above example in FIG. 8 and the like, the case wherethe electron gun assembly 201, the limiting aperture plate substrate202, the blanking deflector 204, the electrostatic lens 205, thelimiting aperture plate substrate 206, the electrostatic lens 207, theelectrostatic lens 208, and the objective deflector 209 are arranged in,for example, a cylindrical electron optical barrel (electron beam column10), but the present embodiment is not limited thereto. In the exampleof FIG. 21, the electron gun assembly 201, the limiting aperture platesubstrate 202, and the blanking deflector 204 are arranged in, forexample, a single cylindrical electron optical barrel (electron beamcolumn 10), and the electrostatic lens 205, the limiting aperture platesubstrate 206, the electrostatic lens 207, the electrostatic lens 208,and the objective deflector 209 are arranged for each beam in a commonspace in the multiple-beam set 12. In the example of FIG. 21, anillustration of the limiting aperture plate substrate 206 is omitted.With such a configuration, each of the electrostatic lenses 205 in themultiple-beam set 12 can be formed of a common substrate. Likewise, eachof the electrostatic lenses 207 in the multiple-beam set 12 can beformed of a common substrate. Likewise, each of the electrostatic lenses208 in the multiple-beam set 12 can be formed of a common substrate.Further, each of the objective deflectors 209 in the multiple-beam set12 can be arranged on a common substrate. Therefore, the multiple-beamset 12 can be formed more easily.

FIG. 22 is a diagram showing still another example of the internalconfiguration of the electron beam column according to the firstembodiment. In the example of FIG. 22, a case where a partition wall 210is arranged between beams in the arrangement space of the electrostaticlenses 205, 207, 208, in addition to the configuration in FIG. 21, isshown. By arranging the partition walls 210 between beams, an electricfield generated by the electrostatic lenses can be prevented fromaffecting adjacent beams. Because the partition wall is intended forelectric field shielding, evacuation efficiency can be increased byusing, for example, a grid structure.

FIG. 23 is a top view showing an example of an electrostatic lens arrayaccording to the first embodiment.

FIG. 24 is a sectional view showing an example of the electrostatic lensarray according to the first embodiment. As shown in FIGS. 23 and 24,each of the electrostatic lenses 205, 207, 208 is formed of a commonsubstrate 212 (213, 214) in the multiple-beam set 12. Each passing hole211 is formed at each beam passing position in such a common substrate.In the example of FIG. 23, for example, when the multiple-beam set 12 isconfigured by the configuration necessary for forming 3×3 beams, 3×3through holes 211 are formed. Besides, the electrostatic lenses 205, 207and 208 are all formed of three stages of electrodes. In the example ofFIG. 24, in the multiple-beam set 12, the electrostatic lens array isformed of common three-stage substrates 212, 213, 214. By applying theground potential to the upper and lower common substrates 212, 214 andadjusting the potential applied to the middle common substrate 213, thelens action for each beam in the multiple-beam set 12 is controlled tobe supplied. When, as shown in the example of FIG. 22, the partitionwalls 210 are arranged between the beams, as shown in FIGS. 23 and 24, aplurality of partition walls 210 may be arranged in a grid pattern.

Next, the operation of actual pattern writing processing using patternwriting data input from outside the lithography apparatus 100 and storedin the storage device 140 will be described step by step.

As an area ratio map creation process (rasterization process), arasterization unit 50 reads pattern writing data from the storage device140 and calculates a pattern area density p′ in a pixel for each of aplurality of pixels (irradiation unit regions) obtained by dividing apattern writing region of the substrate 101 by a size equal to, forexample, a beam size into a mesh shape. The processing is performed for,for example, each of the chip regions 332.

As a dose calculation process, the dose calculation unit 52 firstvirtually divides the pattern writing region (here, for example, thechip region 332) by a predetermined size into a plurality of proximitymesh regions (mesh region for proximity effect correction calculation)in a mesh shape. The size of the proximity mesh region is suitably setto about 1/10 of the range of influence of the proximity effect, forexample, about 1 μm. The dose calculation unit 52 reads the patternwriting data from the storage device 140 and calculates the pattern areadensity p of the pattern arranged in the relevant proximity mesh regionfor each proximity mesh region.

Next, the dose calculation unit 52 calculates a proximity effectcorrection irradiation coefficient Dp (x) (corrected dose) to correctthe proximity effect for each proximity mesh region. The unknownproximity effect correction irradiation coefficient Dp (x) can bedefined by a threshold model for proximity effect correction similar tothe conventional approach using the backscattering coefficient η, thedose threshold value Dth of the threshold model, the pattern areadensity p, and the distribution function g (x).

Next, the dose calculation unit 52 calculates an incident dose D (x)(dose amount) to irradiate the relevant pixel for each pixel. Forexample, the incident dose D (x) may be calculated as a value obtainedby multiplying the preset reference dose Dbase by the proximity effectcorrection irradiation coefficient Dp and the pattern area density ρ′.The reference dose Dbase can be defined by, for example, Dth/(½+η). Fromthe above, the desired incident dose D (x) corrected for the proximityeffect based on the layout of a plurality of figure patterns defined inthe pattern writing data can be obtained.

Then, the dose calculation unit 52 creates a beam irradiation time datamap defining the beam irradiation time for each pixel obtained byconverting the incident dose D (x) for each pixel into the beamirradiation time t gradated in the predetermined quantization unit A.The created beam irradiation time data map is stored in, for example,the storage device 142.

As a beam irradiation time data processing process, a beam irradiationtime data processing unit 54 reads and rearranges the beam irradiationtime data map in the order of shots according to the pattern writingsequence in the first embodiment. Then, the beam irradiation time datais transferred to the deflection control circuit 130 in the order ofshots.

As a pattern writing process, the deflection control circuit 130 outputsa blanking control signal to each of the blanking deflectors 204 in theorder of shots via the relay circuit 184 and also outputs a deflectioncontrol signal to the DAC amplifier 132 in the order of shots. Then,while the stage 105 is continuously moved under the control of the stagedrive circuit 139, the pattern writing mechanism 150 writes a pattern onthe substrate 101 using a bundle (multiple beams) of the electron beam20 irradiated from each of the electron beam columns 10.

According to the first embodiment, as described above, the multiple-beamcluster 16, the multiple-beam block 14, the multiple-beam set 12, andthe multi-column are unitized for each layer and thus, it is easy to addsuch units as necessary and the total electron beam current can beincreased. Further, according to the first embodiment, the irradiationregion of the respective multiple-beam sets 12 is divided by the smallregion 33 smaller than the chip region 332 and thus, the multiple-beamcluster 16, the multiple-beam block 14, or the multiple-beam set 12 thatis unitized can be expanded according to the required throughput.Further, according to the first embodiment, a plurality of substrates101 can be sequentially passed through the irradiation region of each ofthe multiple-beam clusters 16 that are formed as a production line.Therefore, throughput of multiple-beam pattern writing can be improvedand semiconductor substrates (wafers) can be mass-produced.

When writing an LSI pattern on a wafer, overlay accuracy becomesimportant. In this connection, for example, the overlay accuracy can besecured by doing as follows. First, at least three alignment marks areprovided on each wafer. Then, after mounting the wafers on the stage,the wafers are moved and the stage is operated and if a certain wafer isfocused on, the wafer is moved to a plurality of positions (referred toas stage positions), and at each stage position, the position andorientation of the wafer are measured. The measurement can be made by,for example, providing a plurality of optical microscopes between themultiple-beam clusters 16. Further, a portion of the electron beamcolumn can be operated for measurement to determine the mark positionfrom a reflected electron signal obtained by irradiating the mark withan electron beam. Further, the height of the mark is determined using az sensor using an optical lever. Based on the position, orientation, andheight of each wafer at each stage position thus obtained, patternwriting data is corrected and written. Further, accuracy can be improvedby arranging many marks at the boundary of, for example, a die,measuring high order distortion, and correcting the pattern writing databased on the measurement. The measurement is made prior to patternwriting, and in that case, the stage is moved at the same speed as thepattern writing speed. Also, by making the stage speed faster than thepattern writing speed, the time taken for measurement can be shortened.

In the foregoing, an embodiment has been described with reference toconcrete examples. However, the present disclosure is not limited tothese concrete examples. In the above example, for example, the casewhere the objective deflector 209 uses one-stage deflection is shown,but the present embodiment is not limited thereto. The objectivedeflector 209 may use multistage deflection of two or more stages.

Portions of the apparatus configuration, the control method and the likethat are not needed directly for the description of the presentdisclosure are omitted, but a necessary apparatus configuration and anecessary control method can be appropriately selected and used. Forexample, a control unit configuration that controls the lithographyapparatus 100 is not described, but a necessary control unitconfiguration is appropriately selected and used, as a matter of course.

In addition, all charged particle beam lithography apparatuses andcharged particle beam pattern writing methods including elements of thepresent disclosure and the design of which can appropriately be changedby a person skilled in the art are included in the scope of the presentdisclosure.

Additional advantages and modification will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

What is claimed is:
 1. A charged particle beam pattern writing methodcomprising: continuously moving a plurality of substrates aligned in apredetermined direction in the predetermined direction; and writing apattern on the plurality of substrates by using a plurality ofmultiple-beam sets, each irradiating multiple beams, so that eachmultiple-beam set of the plurality of multiple-beam sets sequentiallywrites a portion of the pattern on a different one or more of exposurepixel groups in a same small region, on a same substrate, smaller thaneach die region of a plurality of die regions to form a same pattern,the plurality of die regions provided on each substrate of the pluralityof substrates, in a state where the plurality of substrates iscontinuously moved in the predetermined direction.
 2. The methodaccording to claim 1, wherein the plurality of substrates continuouslymoves along a circulating track, the plurality of multiple-beam sets isarranged along the circulating track, and the plurality of multiple-beamsets writes a pattern on the plurality of substrates such that patternwriting processing of the each substrate is completed by a time wheneach substrate makes one turn or a plurality of turns on the circulatingtrack.